Make browser GPU channel creation async.

ui/compositor/compositor.h

Index: ui/compositor/compositor.h
diff --git a/ui/compositor/compositor.h b/ui/compositor/compositor.h
index d6663038318ba5a4700a111fce70e5604ff21542..fb297685414e04402b453b92522789345f8852f8 100644
--- a/ui/compositor/compositor.h
+++ b/ui/compositor/compositor.h
@@ -69,8 +69,8 @@ class COMPOSITOR_EXPORT ContextFactory {
   // Creates an output surface for the given compositor. The factory may keep
   // per-compositor data (e.g. a shared context), that needs to be cleaned up
   // by calling RemoveCompositor when the compositor gets destroyed.
-  virtual scoped_ptr<cc::OutputSurface> CreateOutputSurface(
-      Compositor* compositor, bool software_fallback) = 0;
+  virtual void CreateOutputSurface(base::WeakPtr<Compositor> compositor,
+                                   bool software_fallback) = 0;
 
   // Creates a reflector that copies the content of the |mirrored_compositor|
   // onto |mirroing_layer|.
@@ -147,6 +147,8 @@ class COMPOSITOR_EXPORT Compositor
 
   ui::ContextFactory* context_factory() { return context_factory_; }
 
+  void SetOutputSurface(scoped_ptr<cc::OutputSurface> surface);
+
   // Schedules a redraw of the layer tree associated with this compositor.
   void ScheduleDraw();
 
@@ -337,7 +339,7 @@ class COMPOSITOR_EXPORT Compositor
 
   LayerAnimatorCollection layer_animator_collection_;
 
-  base::WeakPtrFactory<Compositor> schedule_draw_factory_;
+  base::WeakPtrFactory<Compositor> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Compositor);
 };